So, why doesn't ventrilo fit the bill? You hear everything that Windows Media player or whatever other player you want to use, is playing. You can loop your playlists, turn them off or whatever. Read the post from the link. This is not a hold your microphone up to your speakers thing. I turn off my speakers and use my headphones for talking to the group with my first instance of ventrilo. My second instance of ventrilo broadcasts the music to the server, so everyone can hear. I just have playlists and folders ready to go, so I can loop or switch music easy. If you are playing by text you would not even need the headset or second instance of ventrilo running.
I think some people are put off by installing separate software that they have to learn to use ust to listen to music. I used to raid when I played WoW and Ventrilo was a must. But the Mac version of the program is utter crud for compatibility with Windows clients. Server admins HAVE to know what they're doing and be familiar with the program in order for Mac users to be able to listen/speak over Ventrilo. Coming to MapTool from OpenRPG, my DM's only peeves with the program is the inability to insert a sound clip URL, hit a button, and have it play to everyone in the room. It helped set the mood without worrying about players having problems with a separate program (I suffered terrible Ventrilo disconnects and sometimes server lock-outs).
So, yes, there are other options. Currently, my DM will just host the mp3 to our campaign wiki and he'll post the link to the chat window if he wants us to listen to something. But lately we've just been ignoring music.
It would be a nice feature or separate tool to make. MusicTool; host servers and allow connections where you just play music uploaded from the net or your computer. I could actually see that branching outside of the RPG community to enabling radio DJing to anyone with a music library and an internet connection. Hm...